Composite helmet for body mount

ABSTRACT

A composite helmet is provided for a body mount. The helmet includes an interior structural load bearing skeleton including an elongated cylinder, and a disk or washer mold-bonded with the polymeric or elastomeric portion of the helmet. The elastomeric portion of the helmet includes an elongated axial portion that encompasses the metal cylinder and an over-mold layer, if desired, over the metal disk. In some instances, a ring is incorporated into the shroud for increased strength and rigidity.

This application claims the priority benefit of and hereby expresslyincorporates by reference U.S. provisional application Ser. No.60/354,161, filed Feb. 4, 2002.

BACKGROUND OF THE INVENTION

The present invention is directed to a body mount or cushion assemblyfor an automotive vehicle or truck. More particularly, the presentinvention is directed to a body mount assembly used to insulate orcushion vibration and shock between the frame and vehicle components.

Body on frame vehicles, including trucks, typically include body mountsdisposed between the vehicle components and the frame to providecushioning therebetween. The body mount typically includes a shockabsorbing or vibration absorbing material (a cushioning assembly) suchas an elastomeric member and a shell or helmet formed of sheet metalthat overlies or enshrouds the elastomeric member. The helmet istypically constructed as a single piece of deep-drawn steel. This is atooling intensive process and requires the designer to providesufficient material thickness to achieve suitable crush loads.

The deep-drawn helmet is generally bell-shaped and when contactedoccasionally produces an undesirable clanging. Thus, noise reductionassociated with the mount assembly is desirable.

Forming the entire helmet of metal substantially adds to the mass of theoverall mount assembly. A reduction in the use or amount of metal usedin the mount assembly would contribute to weight reduction associatedwith the vehicle.

In addition, known body mounts require plating on the metal componentsthereof to increase corrosion resistance. Alternative strategies ofproviding an effective body mount that has increased corrosionresistance without sacrificing performance is always desired.

In addition, ease of assembly is a goal associated with mass productionof a vehicle. Thus, any modification to the mount assembly needs toaddress issues regarding ease of manufacture and assembly.

The mount assembly can also be tuned to address different forces in thefore and aft directions, as well as laterally. Different vehicles usingessentially the same mount assembly experience different forces. Thus,it is desirable to provide desired tuning to allow greater flexibilityin system design.

SUMMARY OF INVENTION

A composite helmet assembly of a vibration isolator or mount assemblymanufactured in accordance with the teachings of the present inventionhas a substantially reduced mass than a comparable steel version.

The composite helmet assembly includes an inner skeleton of distinctstructural load bearing components that are joined together. Forexample, an annular plate and an elongated cylinder are mold bondedtogether in an integrally molded helmet. This assembly is received overthe shank of a mounting bolt, and cooperates with an upper cushionassembly disposed on one side of the frame and assembled to a lowercushion member or body mount assembly on the other side of the frame.

Increased tuning flexibility is also achieved with this arrangement as aresult of the wide array of capabilities of the molded component.

A common structural load bearing assembly or skeleton may be usedwithout sacrificing tuning abilities.

Another benefit resides in the potential to significantly reduce toolcost and lead time by eliminating expensive and complicated deep-drawdies.

The composite helmet allows for increased flexibility in loaded height,i.e., the component is not constricted by deep-draw shapes.

An opening through the upper cushion assembly may be dimensioned toprovide a temporary retention force that maintains the individualcomponents in pre-assembled relation to facilitate final assembly.

A primary advantage of the invention resides in reduction in mass of theassembly.

Still another advantage of the invention is the ability to eliminate anyanti-corrosion coating.

Still another advantage resides in the temporary bolt retention featureto simplify assembly.

Increased friction between the cushion and the helmet leads to a moreconstant vibration damping rate over time.

Still other features and advantages of the invention will becomeapparent to one skilled in the art upon reading and understanding thefollowing detailed description.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a longitudinal cross-sectional view of a composite helmet bodymount.

FIG. 2 is an exploded view of the individual components shown assembledin FIG. 1.

FIG. 3 is a perspective view of the composite helmet with selectportions cut away for ease of illustration.

FIG. 4 is a view similar to FIG. 3 with selected portions of thecomposite helmet removed and illustrating the underside of the helmet.

DETAILED DESCRIPTION OF THE INVENTION

Turning initially to FIG. 1, the assembled body mount assembly A isillustrated. It includes a first or upper body mount portion 10 and asecond or lower body mount portion 12 disposed on opposite sides of avehicle frame 14. The lower body mount portion, also referred to as arebound cushion assembly, includes a metal clamp disk 16 having acentral opening 18 for mounting purposes. The metal clamp diskabuttingly engages cushion member 20, preferably an elastomeric materialthat provides desired energy damping or vibration attenuation. As shownhere, the lower cushion member is a generally cylindrical structure thatabuts a surface of the frame at a first or upper end 22 and may includea recess at a second or lower end 24 for receipt of or abuttingengagement with the metal disk. Of course, one skilled in the art willappreciate the lower cushion member may adopt a wide variety ofconfigurations as may be required for a particular design. For example,the lower cushion may be configured to provide different rates ofattenuation in different directions, or provide multiple cushioning rateratios to allow the design flexibility of a vehicle ride. Furtherdetails of an exemplary embodiment of alternative lower cushionconfigurations are shown and described in commonly owned U.S. Pat. No.6,030,016-Rice, as well as other known prior art. The present invention,therefore, should not be unduly limited to the particular structuralarrangement of the lower cushion as shown in the present application.

The upper body mount portion includes an upper cushion member 30. Theupper cushion member is preferably molded to a metal collar 32 having aradial portion 34 adapted for engagement with an upper surface of theframe and an axial portion 36 that extends through central opening 38 inthe frame. In the embodiment of FIG. 1, the upper cushion member is ahollow cylindrical configuration with a counterbore or recess 40 havinga diameter slightly greater than the through opening or bore 42. Ofcourse it will be appreciated by those skilled in the art that otherconfigurations of the upper cushion member may be used without departingfrom the scope and intent of the invention. The cushion member ispreferably formed of an elastomeric material that also provides desiredenergy damping or vibration attenuation. As perhaps best illustrated inFIG. 2, the opening 38 through the frame may be non-circular, so thatthe metal collar and/or upper cushion member would have a matingconfigured surface intended to prevent relative rotation between thesecomponents. This non-circular opening also assures proper orientation ofthe mount within the vehicle. As was the case with the lower cushionmember, the present invention should not be limited to the particularstructural arrangement of the upper cushion as shown and describedherein. Rather, it will be appreciated that other configurations can beused without departing from the scope and intent of the presentinvention.

A helmet 50 formed in accordance with the present invention extends inat least partially overlying relation with the upper cushion member, andfurther includes a portion that extends into or through the hollowcentral opening of the upper cushion member. In the exemplaryembodiment, the helmet is a composite structure that is comprised of amolded polymer or elastomeric material that includes an inner skeletonof a load bearing structural components. Here, the polymer/elastomericmaterial is symmetrical about a central vertical axis, although it willbe recognized that the material can adopt a wide variety of differentconfigurations as may be necessary to address the particular energydamping needs of an automotive vehicle. The inner skeleton of the helmetincludes a metal, cylindrical portion 52 received in a central opening54 of the molded polymer/elastomer material. As shown, the metalcylinder 52 is axially co-extensive with and adds increased strength tothe inner diameter of the polymer/elastomer material. A metal disk orwasher component 56 is another part of the metal skeletal portion of thehelmet. Although it is appreciated that the disk could be integrallyformed with the cylindrical portion 52, the ability to use separate,simplified structures for the metal skeletal portion of the helmetdesign reduces the manufacturing complexity and thereby the cost ofthese components. The more difficult shapes of the composite helmet thatare desired can then be limited to the non-metal, molded material thatforms the majority of the helmet and that can be easily modified withmold inserts or the like. The metal disk is located at an upper end ofthe metal cylinder for abutting engagement therewith and in theexemplary embodiment is preferably received in a recess 58 of theenlarged diameter portion of the helmet. A seal ring 60 overlies themetal disk if desired and prevents moisture from reaching the metalcomponents of the helmet. This eliminates the need to provide acorrosive-resistant coating on the metal components, or to provide drainopenings or channels in the.

The polymer/elastomer portion of the helmet includes an axiallyextending portion 70 that is molded over the outer diameter of thecylinder 52 along its entire length. The axially extending portion has atapering or other complex asymmetrical shaped surface 72 over itslength. Again, and as will be appreciated by those skilled in the art,it would be more difficult to form the tapering or other complexasymmetrical conformation in a metal component yet in accordance withpreferred embodiment, the complex shape can be more easily accommodated.The outer surface 72 of the axial portion provides increased frictionbetween the helmet and the upper cushion member along the interfacebetween surfaces 72 of the helmet and the opening 42 of the uppercushion member. The increased friction results from the surface finishof the components leads to more constant tri-axial rates over time byreducing rubbing wear between the cushion and the helmet in comparisonto prior arrangements.

The axial portion 70 of the helmet merges into a radial flange 74 at itsfirst or upper end that includes a shroud or rim 76 extending downwardlyfrom an outer periphery of the flange. The flange and shroud encase orcover the upper cushion member in substantially the same manner as aprior art metal helmet. In the embodiment of the present invention, theshroud is shown as a circumferentially continuous surface although itwill be appreciated that in selected applications the shroud can bediscontinuous. For example, the shroud or flange may be other complexshapes and molded thereabout to address different forces imposed on thecushion assembly.

A fastener or mounting bolt 90 includes enlarged head 92 at a first endand an elongated shank 94 extending therefrom that passes through theclamp disk, lower cushion member, upper cushion member, and the metalcylinder 52 disposed in the axial portion of the helmet. A terminal endof the shank protrudes or extends outwardly from the upper end, i.e.,through the metal washer 56, and may be externally threaded forcooperation with a threaded fastening nut (not shown) or otherwisesecured at its terminal end to hold the individual components of thecomposite helmet together.

FIG. 2 illustrates the individual components of the body mount assemblyin an exploded view. The seal ring 60 can be molded into the assemblyfor assembly plant convenience, i.e., to hold the fastener in place andfacilitate handling.

The profile of the helmet, and for example, the shroud 76, can also bemodified as demonstrated in FIGS. 3 and 4. As shown here, the lowerridge is slightly enlarged to receive a strengthening ring, such asglass reinforced nylon ring 100, molded therein. The ring providesincreased rigidity or strength and stability to the structure whilemaintaining encapsulation of the metal components to limit problems withcorrosion, and it will be appreciated that the particular conformationor material of construction need not be limited to the nylon ring assown and described. Moreover, the ring only defines a minor portion ofthe shroud so that the total mass of the assembly is minimized.

In this manner and in accordance with the present invention, a knownbody mount helmet typically constructed from a single piece ofdeep-drawn steel is replaced with an assembled, molded arrangementhaving an interior metal skeleton that does not corrode, does notproduce clanging associated with the prior metal helmets, temporarilyretains a bolt in place, has a substantially reduced mass relative tothe prior all-metal version, and allows great flexibility to introducedifferent levels of pre-compression in differing directions of thecushion, i.e., allowing for greater system tuning flexibility ifdesired. In addition, the invention allows the use of a common skeletalmember without sacrificing tuning abilities, and can potentiallysignificantly reduce tool cost and lead time by eliminating expensiveand complicated deep-draw dies. Development of components or parts isaccelerated and due to the molded nature of the component, interiorfeatures can be easily molded into the assembly, e.g., to hold thefastener in place temporarily. The inner skeleton or structural loadbearing assembly includes an elongated support portion 70 and a radialportion 56 in load bearing relation therewith, that is received in amoldable material. The moldable material is a hard EPDM elastomer in thepreferred arrangement but any moldable substance such as thermoplastics,glass reinforced nylon, etc., can be used depending on the rigors of theapplication. Likewise, although the inner skeleton is shown anddescribed in the preferred embodiment as a metal, other structuralmaterials suitable to load conditions can be used interchangeably.

The invention has been described with reference to the preferredembodiment. Obviously, modifications and alterations will occur toothers upon reading and understanding the preceding detaileddescription. It is intended that the invention be construed as includingall such modifications and alterations.

1. A vibration isolator comprising: a cushion assembly; and a compositehelmet including a structural load bearing assembly for receiving torquefrom an associated fastener that secures the cushion assembly and helmettogether, the load bearing assembly including an elongated supportportion and a radial portion in load bearing relation with the elongatedsupport portion for transferring loads therebetween, and a moldablematerial received around at least portions of the load bearing assembly.2. The vibration isolator of claim 2 wherein the elongated supportportion is a generally cylindrical member that extends into the cushionassembly.
 3. The vibration isolator of claim 2 wherein the elongatedsupport portion is a metal cylinder.
 4. The vibration isolator of claim3 wherein the radial portion is an annular disk having a central openingdimensioned to receive the associated fastener therethrough.
 5. Thevibration isolator of claim 4 wherein the disk is metal and abuttinglyengages the metal cylinder.
 6. The vibration isolator of claim 1 whereinthe radial portion is an annular disk having a central openingdimensioned to receive the associated fastener therethrough.
 7. Thevibration isolator of claim 6 wherein the disk is metal and abuttinglyengages the metal cylinder.
 8. The vibration isolator of claim 1 whereinthe moldable material is a polymer.
 9. The vibration isolator of claim 1wherein the moldable material is an EPDM.
 10. The vibration isolator ofclaim 1 wherein the moldable material encases the structural loadbearing assembly to seal the structural load bearing assembly frommoisture.
 11. The vibration isolator of claim 10 wherein the moldablematerial includes a shroud extending about the periphery of the radialportion and partially enclosing the cushion assembly.
 12. The vibrationisolator of claim 11 wherein the shroud includes a high tensile strengthinsert therein.
 13. The vibration isolator of claim 1 wherein theelongated support portion extends axially outward from the radialportion, the elongated support portion extending into the cushionassembly and the radial portion abutting one end of the cushionassembly.
 14. The vibration isolator of claim 13 wherein the moldablematerial encases the elongated support portion and the radial portion toseal the structural load bearing assembly from moisture.
 15. A vibrationisolator for damping vibration energy between an associated automotivecomponent and an associated vehicle frame, the vibration isolatorincluding: a generally annular cushion assembly dimensioned for receiptbetween the associated automotive component and the associated vehicleframe; a composite helmet interposed between one of the associatedautomotive component and the associated vehicle frame and the cushionassembly, the helmet including a load bearing skeleton and a moldablepolymer received at least partially therearound.
 16. The vibrationisolator of claim 15 wherein the load bearing skeleton includes anelongated stiffener extending through the annular cushion assembly. 17.The vibration isolator of claim 16 wherein the elongated stiffener is ametal construction.
 18. The vibration isolator of claim 16 wherein theload bearing skeleton includes a disk in abutting engagement with oneend of the stiffener.
 19. The vibration isolator of claim 18 wherein thedisk is a metal construction.
 20. A method of manufacturing a helmet ofa vibration isolator that includes a cushion assembly, the methodcomprising the steps of: providing a load bearing skeleton; and forminga moldable material around the skeleton configured to extend into thecushion assembly and at least partially enshroud one end of the cushionassembly.